What I found in an old biology textbook
I was in an old one room school house and found an old biology text book. I am fascinated with old school text books. I like to see different things were back then.
I couldn't find what year it had been published, but it was clearly quite old. Flipping through the pages, I found something peculiar. A whole chapter on the genetics of humans! Including the inheritance of intelligence, and even suggestions of Eugenics. Something still controversial today.
I took some pictures of the chapter. I just decided to transcribe the whole thing, for anyone else interested.
From the text book Our World of Living Things:
TOPIC 3. THE MENDELIAN LAWS OF HEREDITY APPLY TO MAN
Do the laws of heredity apply to man?
What do you conclude from the family histories of the Edwards family, the Jukes family and the Kallikaks?
What characters in men are known to be inheritable?
Are diseases acquired or inherited?
Is intelligence acquired or inherited?
Are feeble-mindedness and insanity inherited?
SUGGESTIONS AND HELPS FOR STUDY
This is an important topic. It deals with human inheritance. Study it carefully. We can not hope for rapid progress in civic betterment along biological lines until the general public understands the part heredity plays in human life.
Try to read one or more other books that treat the topic of human heredity more extensively than it has been possible to treat it here.
Study the following words. They will be used in this topic.
albinism - the absence of pigments in the skin, hear, leathers, and eyes.
pigment - a coloring matter.
pigmentation - coloration with pigment.
delinquent - one who commits a fault or a crime.
READINGS AND ACTIVITIES WHICH WILL HELP ANSWER THE PROBLEMS AND QUESTIONS
Do the laws of heredity apply to man? The laws of heredity were discovered by experimenting on plants and lower animals. The question arises now as to whether the laws of heredity apply to man. Have you ever observed resemblances between members of the same family? Perhaps you have heard people discuss resemblances between brothers and sisters. These common observations have been verified by careful scientific studies. Human characters such as color of hair, color of eyes, skin color, intelligence, and physical defects have been traced through generations of families. All available scientific evidence indicates that many human characters follow the Mendelian laws of inheritance.
When we wish to study hereditary traits in a species of plant or a species of lower animal, we simply breed some of the species together and observe the results. Direct experiments like this are not permissible with human beings. Data must be collected by studying and analyzing family histories. Unfortunately many families do not keep complete family records; hence it is a difficult task to obtain data on physical and mental traits of persons three, four, or five generations back.
What do you conclude from the family histories of the Edwards family, the Jukes family, and the Kallikaks? Certain American families have been traced through many generations to determine the traits that occur. The Edwards family, which has been studied in this manner, shows the value of good inheritance.
Jonathan Edwards, an eminent thinker, lived in New England during colonial times. In 1900, records of 1394 of his descendants were studied. The facts that follow show the outstanding achievements of this notable family.
100 clergymen, missionaries, or theological professors
75 officers of army and navy
Winship states that almost if not every department of social progress and of public weal has felt the pulse of this healthy, long-lived family. It is not known that any of them was ever convicted of a crime.
A striking contrast to the Edwards family is [3 letters untranscribable]ished by the Jukes family. Max Jukes, a lazy and degenerate backwoodsman who lived in the state of New York, was the founder of the Jukes family of defectives, of which about twelve hundred descendants have been traced. It includes -
400 physical wrecks from debauchery
At the time of this record was made this family had already cost the state of New York $1,250,000. All this crime, immorality, and expense to the state might have been avoided if the original ancestor had been prevented from producing offspring.
FIG. 267. FAMILY HISTORY OF THE KALLIKAKS
Perhaps the most convincing study of human inheritance is that of the Kallikaks. It is especially important because it contains a normal and a defective strain. While a soldier in the Revolutionary War, Martin Kallikak (a fictitious name) mated with a feeble-minded woman and became the father of a son. Of 480 descendants of this son traced in 1912, 143 were feeble-minded and most of the others were criminal, immoral, or inebriate. Not a single individual of exceptional ability was found.
After the revolutionary War, Martin Kallikak married a grl from a normal family. Of the 4?? descendants traced from this union, most were succesful persons such as educators, physicians, lawyers, merchants, land owners, etc. Not a single case of feeble-mindedness was found. Would you conclude from this family history that heredity was largely the determining factor of the differences in the two different lines of Kallikaks?
What characters in man are known to be inheritable? Investigation has shown that certain physical and mental traits in man are inherited. These characters are passed from parent to offspring in accordance with the laws of heredity. The following table [untranscribable] some of the characters of man that are either dominant or recessive traits.
Dominant character Recessive character Brown eyes Blue eyes Dark hair Light hair Curly hair Straight hair Nervous temperament Phlegmatic temperament Normal intelligence Very little intelligence Normal intelligence Very great intelligence
The following table is interesting because it shows that certain defects and susceptibility to certain diseases are inheritable. Notice that certain diseases are dominant traits, whereas others are recessive traits.
Dominant character Recessive character Webbed fingers or toes Normal hands and feet Extra finger or toe Normal hands and feet Dwarfed limbs Normal limbs Hairless or toothless condition Normal condition Cataract of eye Normal eye Short fingers or toes Normal fingers and toes Normal intelligence Feeble-mindedness Normal condition Susceptibility to tuberculosis Normal pigmentation Albinism (lack of pigmentation) Normal condition Lack of muscular control Baldness (in men) Baldness (in women)
Exercise. How many Mendelian characters can you identify in your own family? Try to make a tabulation or chart of the occurrence of Mendelian characters in your own family. Tabulate your data for such characters as eye color, texture of hair, color of hair, temperament, complexion, and defects.
Are diseases acquired or inherited? This is an important question and a difficult one to answer. In the first place, what is a disease? Disease is frequently defined as any unhealthy condition or effect in the body. We believe that every disease has a cause or sometimes a combination of many causes, but the nature of some diseases is not yet well understood. Diseases may result from improper eating, from germs, from injuries, from unhealthful occupations, from worry, and from other causes.
Germ diseases are not inherited. Germs are tiny microscopic plants or animals present in our environment. To become afflicted with a germ disease a person must fist come in contact with the germ which causes the disease. Germs are not transmitted from parents to offspring by heredity because germs never reside in the chromosomes.
However, a person may be born with a prior resistance to a certain disease. This is believed to be true for tuberculosis and cancer. In man almost any individual many contract tuberculosis if his vitality becomes reduced sufficiently, but there is little doubt that certain families are more easily infected than others and much less resistant to the ravages of the disease, once the germs have gained a foothold. Nevertheless, it is also important to keep in mind that susceptibility to a disease is vastly different from inheriting the actual disease. It does not follow that because a person is susceptible to a certain disease he must come down with it. Every advance we make toward better sanitation and more healthful living decreases the chances of infection.
The following defects, frequently thought of as diseases, seem to be inherited as recessive characters: St. Vitus' dance, Thomsen's disease (lack of muscular tone), tendency to bronchial asthma, various forms of paralysis, enlarged eye, pernicious anemia, stammering, nosebleed, and a tendency towards such illnesses as certain forms of rheumatism, migraine, pneumonia, hernia, spasmodic croup, gout, and goitre.
Is intelligence acquired or inherited? By intelligence is meant the native capacity for learning or the ability to learn. One scientist, in a study of 977 men of genius, found a total of 535 near relatives as eminent relatives as he found for 977 average men. Studies of identical twins show that when they are placed in quite different environments at an early age, they nevertheless remain quite similar in mental traits during their lifetime. It has also been observed, and probably you have noticed it too, that when children of the same family differ greatly from each other in mental ability, they usually continue to differ despite the fact that they have been reared in a similar environment. All available data indicate that intelligence is determined by the genes which a person inherits.
Are feeble-mindedness and insanity inherited? Feeble mindedness and insanity are not the same. Scientists make a sharp distinction between these two defects. Feeble-mindedness is a mental deficiency, a lack of intellectual capacity. It is present at or near birth. Insanity, on the other hand, is a degeneration of the nervous system. An insane person was a normal person for awhile, but later lost all or part of the mentality he once had.
FIG. 268. THREE MARRIAGES WHICH INDICATE HOW FEEBLE-MINDEDNESS IS INHERITED
There are various grades of feeble-mindedness. Idiots are the lowest type. Their mentality never develops beyond that of an average two-year-old child. They are as helpless as a baby. Imbeciles can take care of themselves in a crude way but are unable to earn a living. Their intelligence ranges from that of an average three-year-old child to that of an average seven-year-old child. Morons are more or less self-supporting types. Their intelligence is equivalent to that of normal seven to twelve-year-old children. Morons present the most serious problems to society. Idiocy and imbecility are usually detected early and are kept, more or less, under restraint. Morons are not so easily recognized and become, very frequently, the shiftless, ne'er-do-well types that are present in every community. Closely associated with feeble-mindedness is epilepsy. Guyer, a noted American biologist, defines epilepsy as a disease characterized by"fits" or convulsive attacks in which generally there is a loss of consciousness. The attacks vary in frequency of occurrence and in severity. The attacks may vary in length from five to twenty minutes or longer.
There are many different kinds of insanity; how many has not yet been determined. Also there seem to be many different causes, Some forms are acquired, others are inherited. Probably not more than 50 percent of the cases of insanity are directly or indirectly due to heredity.
It has been definitely established that feeble-mindedness is the basic cause of much of our delinquency, crime, and poverty. In view of this fact, is it not important that we devise methods to eliminate hereditary feeble-mindedness and hereditary insanity from human society?
Exercise. Is feeble-mindedness inherited? The chart , Figure 268, shows three marriages among feeble-minded people and the offspring produced. Study this chart carefully and describe in writing the results of these marriages.
SUMMARY OF IMPORTANT IDEAS
Physical and mental traits of man pass from parents to offspring in accordance with the laws of heredity.
Germ diseases arre not inherited. A susceptibility to certain germ diseases may be inherited. This seems to be true of tuberculosis and cancer.
Intelligence is inherited.
Feeble-mindedness is the basic cause of much of the crime, poverty, and delinquency in human society.
REFERENCES FOR FURTHER STUDY
Aftwood and Heiss, Educational Biology, Unit VI
Conklin, Heredity and Environment in the Development of Man
East, Biology in Human Affairs
Guyer, Being Well-Born
Hunter, Problems in Biology, Unit XVIII
Peabody and Hunt, Biology and Human Welfare, Chapter XXVII
What and Fitzpatrick, General Biology, Chapter XXXV
Wiggam, The Fruit of the Family Tree
[multiple choice test questions excerpted]
Conklin, Heredity and Environment
Downing, The Third and Fourth Generation
Goddard, The Kallikak Family
Guyer, Being Well-Born Jordan, The Heredity of Richard Roe
Locy, Biology and it's makers
Wiggam, The Fruit of the Family Tree